1. Technical Field
The present disclosure relates to light emitting diode (LED) illuminating devices, especially to an LED illuminating device with large light divergence angle.
2. Description of Related Art
Compared to many other kinds of illuminating devices, LEDs have many advantages, such as high luminous efficiency, low power consumption, and long service life. Yet, LEDs still have disadvantages. Because light emitted by LEDs is directional, the light divergence angle of an LED illuminating device is generally less than that of some other kinds of illuminating devices, such as an electric incandescent lamp, a fluorescent lamp and a halogen lamp.
Referring to FIG. 1, the light divergence angle of a typical LED illuminating device 401 is about 60 degrees, which is less than an electric incandescent lamp. Referring to FIG. 2, a conventional ring-shaped LED illuminating device including a number of substrates is shown. With the configuration of multiple substrates, the light divergence angle of the LED illuminating device increases. However, more heat is produced by the LEDs (shown as arrows) on the substrates, which requires an efficient heat dissipation device, adding cost and complexity to structure of the LED illuminating device.
Therefore, what is needed is an LED illuminating device with large light divergence angle.